/*
 * Copyright 2008 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.dotspots.rpcplus.client.flexiblerpc.impl;

import com.google.gwt.core.client.GWT;
import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.core.client.UnsafeNativeLong;
import com.google.gwt.user.client.rpc.IncompatibleRemoteServiceException;
import com.google.gwt.user.client.rpc.SerializationException;
import com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamReader;
import com.google.gwt.user.client.rpc.impl.Serializer;

/**
 * For internal use only. Used for server call serialization.
 */
public final class ClientSerializationStreamReader extends AbstractSerializationStreamReader {

	private static native JavaScriptObject eval(String encoded) /*-{
		return eval(encoded);
	}-*/;

	private static native int getLength(JavaScriptObject array) /*-{
		return array.length;
	}-*/;

	@UnsafeNativeLong
	private static native long readLong0(double low, double high) /*-{
		return [low, high];
	}-*/;

	int index;

	JavaScriptObject results;

	JavaScriptObject stringTable;

	private Serializer serializer;

	public ClientSerializationStreamReader(Serializer serializer) {
		this.serializer = serializer;
	}

	@Override
	public void prepareToRead(String encoded) throws SerializationException {
		results = eval(encoded);
		index = getLength(results);
		super.prepareToRead(encoded);

		if (getVersion() != SERIALIZATION_STREAM_VERSION) {
			throw new IncompatibleRemoteServiceException("Expecting version " + SERIALIZATION_STREAM_VERSION + " from server, got "
					+ getVersion() + ".");
		}

		stringTable = readJavaScriptObject();

		// TODO:
		// popTimingData(stringTable);
	}

	public native String popTimingData(JavaScriptObject stringTable) /*-{
		return stringTable.pop();
	}-*/;

	public native boolean readBoolean() /*-{
		return !!this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::results[--this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::index];
	}-*/;

	public native byte readByte() /*-{
		return this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::results[--this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::index];
	}-*/;

	public native char readChar() /*-{
		return this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::results[--this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::index];
	}-*/;

	public native double readDouble() /*-{
		return this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::results[--this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::index];
	}-*/;

	public native float readFloat() /*-{
		return this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::results[--this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::index];
	}-*/;

	public native int readInt() /*-{
		return this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::results[--this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::index];
	}-*/;

	public long readLong() {
		if (GWT.isScript()) {
			return readLong0(readDouble(), readDouble());
		} else {
			return (long) readDouble() + (long) readDouble();
		}
	}

	public native short readShort() /*-{
		return this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::results[--this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::index];
	}-*/;

	public String readString() {
		return getString(readInt());
	}

	@Override
	protected Object deserialize(String typeSignature) throws SerializationException {
		int id = reserveDecodedObjectIndex();
		Object instance = serializer.instantiate(this, typeSignature);
		rememberDecodedObject(id, instance);
		serializer.deserialize(this, instance, typeSignature);
		return instance;
	}

	@Override
	protected native String getString(int index) /*-{
		// index is 1-based
		return index > 0 ? this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::stringTable[index - 1] : null;
	}-*/;

	private native JavaScriptObject readJavaScriptObject() /*-{
		return this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::results[--this.@com.dotspots.rpcplus.client.flexiblerpc.impl.ClientSerializationStreamReader::index];
	}-*/;

}
